1. Field of the Invention
The present invention relates to retaining devices, and more particularly to wrist band secured devices for retaining portable calculators.
2. Description of the Prior Art
As advances in solid state physics and miniaturization go forth the size of calculators continues to decrease, often with a concurrent increase in functions. Typically, however, the calculator, whether it be simple or complex, requires both the facilities for manual input and a visual read-out, each of these dictating a minimum size beyond which further decreases are no longer practical. Thus, the size of a calculator with present day technology, is most often determined by the functions provided, i.e. by the number of manual inputs which are necessary in order to select these functions.
As a result of this miniaturization there has been a recent trend incorporating a calculator in a wrist watch module. This utility in deploying a calculator on the wrist of a person has had first recognition in the art of digital watches where the logic provided to implement the clock is also used to perform some of the most basic calculations. Thus, for example, in U.S. Pat. No. 3,298,960 this exact feature is achieved, this patent providing the concurrent use of the same digital logic to maintain time and to perform calculations. In this configuration, however, the face of the calculator is necessarily limited to the size of a typical watch, and the number functions and manipulative convenience are therefore highly limited. In addition, the physical structure of the housing is particularly directed to contain one specific circuit, and is therefore not adapted to expanded use.